Psalm 21

To the Chief Musician. A Psalm of David.....

To the Chief Musician. Set to “The Deer of the Dawn.” A Psalm of David.

Read chapter 21
The little words before verse one are called the superscript and the little words after the last verse are called the subscript.  It's hard to tell from the translators which super and sub script go with what Psalm since it's not actually a verse.   Dependent on what each psalm says we can figure out what title and ending gives to each Psalm.  Also from Habakkuk 3 we can tell psalms were written this way with titles at the end as that chapter is a song that ends "To the Chief Musician..."  So what's with the "to the tune of the Deer of the Dawn"?  For one we no longer have or know any tunes of that day, so we can't really know how this was sung or what beat it had.  The Hebrew words are "Aijeleth Shahar" and should be translated "Relating to the Day Dawn."  This helps us make more sense as relating to the day when Christ dawns at last and His future kingdom is here.  This makes sense with Psalm 21 in David's praise of his prayers being answered and his future plans in the earth and the judgement to come on God's enemies.  Chapter 22 has to do with Christ's death and nothing to do with the dawning of the kingdom.  So we understand this phrase of the Psalm that God put in, and not just a heading by man in different Bible versions, we can understand the subject and context. 
So how or what do you look forward to that future dawning day of Christ?